1. Field of the Invention
The present invention relates to a transistor, and more particularly, to an organic thin film transistor, a display device using the same and a method of fabricating the same. Although the present invention is suitable for a wide scope of applications, it is particularly suitable for forming an organic thin film transistor for a flexible display device.
2. Description of the Related Art
A thin film transistor (TFT) that is widely used in display devices generally includes an amorphous or polycrystalline silicon as a semiconductor layer, a silicon oxide layer as a gate insulating layer, and a metal layer as a gate electrode. Recently, with the development of a variety of semiconductive organic materials, many researchers world-wide are actively developing a TFT using an organic material as the semiconductor layer. The organic semiconductor material can be synthesized by various methods into polymer. Such an organic semiconductor material is flexible, inexpensive to produce, and easy to mold into a fiber or a film. Therefore, the organic semiconductor material is increasingly used in various types of display devices.
Recently, competition for developing a flexible LCD device is becoming intense. A flexible LCD device is portable because the flexible LCD device is thin and can be rolled-up. Accordingly, visual information can be conveniently viewed anytime and anywhere, if the flexible LCD device becomes practical and a network/storage capability is also implemented with such a practical flexible LCD device. The academic and the industrial community estimate that an early prototype flexible LCD device will enter the market next year and be popular by 2010.
In a flexible LCD device, both the display unit and the switching unit should have flexibility. Research is actively being conducted in replacing a glass substrate of prior display units with a plastic substrate to provide flexibility to the display unit. Further, research is actively being conducted in replacing the amorphous or polycrystalline silicon in the semiconductor layer of a prior TFT with an organic semiconductor material to form an organic thin film transistor (OTFT). However, forming the OTFT with the organic semiconductor material is more complex to produce since an additional process, such as a surface treatment, is required for patterning an organic semiconductor layer.